1. Field
Embodiments discussed herein relate to wireless communication, such as multi-radio or cognitive radio.
2. Description of the Related Art
Multi-radio or cognitive radio refers to a framework for wireless communication where a network or wireless node change their transmission and/or reception parameters so as to communicate more efficiently by avoiding interference with other licensed or unlicensed nodes or users. The change of transmission or reception parameters can be based on the active monitoring of a number of factors within the internal and external radio environment, including radio frequency spectrum, user behavior, and network state.
Full cognitive radio is a type of cognitive radio in which every possible parameter observable by the network or wireless node is taken into account when deciding on transmission and reception changes. Spectrum sensing cognitive radio is a type of cognitive radio in which only the radio frequency spectrum is considered when deciding on transmission and reception changes. Further, cognitive radio can be distinguished on the basis of the parts of the spectrum available. For instance, licensed band cognitive radio refers to cognitive radio that is capable of using bands assigned to licensed users; whereas unlicensed band cognitive radio refers to cognitive radio that can only utilize unlicensed parts of the radio frequency spectrum.
As mentioned above, one function of cognitive radio is to utilize spectrum sensing techniques to detect the unused spectrum and use it while avoiding harmful interference with other nodes or users. Another function of cognitive radio is to provide spectrum management functions by capturing the best available spectrum band to meet communication requirements, such as quality of service requirements. Cognitive radio also supports spectrum mobility by allowing a cognitive radio user to exchange its frequency of operation. In addition, cognitive radio can provide spectrum sharing by providing a fair spectrum scheduling method.